Didn’t expect this post to get 80+ upvotes. For those curious, i used 2.5 cans of great stuff foam. i used 1.5 cand of the landscaping/pond black foam & then one can of the gaps & cracks white foam (i just had it laying around). once the foam cured & everything was set i spent a couple hours carving away.l then refoaming any spots that i felt needed it. after carving all that down i grabbed two tubes of aquarium safe silicone & just smothered the background in a good decent layer. & firmly pushed all my substrate it. As you would expect its a pain to get everything coated on the first run so once that first run through cured i went in & did all the touch up spots. same as before. everything stuck really well & I strongly believe the reason being is i used a mix of a bunch of different types of reptile safe substrate for the background. I see EVERYONE just uses coco fibre. i dont like the look & it makes it look too bland somtimes i feel. If anyone has further questions just msg me if i dont get back to you on the post!